Flashing light last night(!)

[TwoPi]

Hi,

I was watching an Iridium flare last night (star chart from HeavensAbove below) and just as it finished I noticed another satellite in the same area of the sky but moving in the opposite direction (i.e. picked it up in Bootes and then saw it heading towards Draco). It was probably about mag 3ish but brightened (just like a flare) to about mag 0ish. It then faded quickly as you would expect, but then brightened again. It probably did this 4 or 5 times, every few seconds or so.

I guess it must have been a tumbling satellite but looking on both HeavensAbove and CalSky I can't see a likely candidate. According to CalSky there were a few tumbling Iridiums at that time but not in that part of the sky / with that trajectory.

Anyone else see it or have any ideas which satellite it was?

[TwoPi]

Just realised, I probably should have posted this in Observing - Widefield, Special Events and Comets. Apologies Mods!

[Pondus]

How about Adeos Rocket?

 It should pass Bootes at 10:10 pm heading for Draco/Cepheus

Rune

[TwoPi]

Hi Rune, I think that might be a little late - we noticed it as soon as the Iridium flare finished around 22:01 - 22:02.

However, having found a new bit on CalSky ('Satellites within interval') I've just tried searching for all satellites visible between 21:55 and 22:05 last night and it gives me a few candidates, the most promising of which seems to be Yaogan 18 Rocket ( 39364 2013-059-B ).

There's nothing to indicate it is tumbling but it seems like the right track, predicted magnitude (except the flaring of course) and spot on in terms of timing.

Appears      22h00m31s   2.9mag  az:100.2° E    h:47.8°
Culmination  22h00m58s   2.9mag  az: 71.6° ENE  h:51.7°
 distance: 606.3km  height above Earth: 486.1km  elevation of Sun: -19°  angular velocity: 0.70°/s
at Meridian  22h03m27s   5.8mag  az:  0.0° N    h:17.5°
 

Does it sound likely that this could produce periodic flares in magnitude?

[Pondus]

My guess is that a spinning satellite would produce 'periodic flares' in magnitude.

One part of the satelitte reflecting more light from the sun than other parts...

just a guess though.

Rune